Answer:
b. The DNA fragments move towards cathode under electric field through the matrix.
Step-by-step explanation:
Gel electrophoresis is a molecular biology technique used to separate DNA fragments based on size using electric current. The electric current passes through a GEL (agarose gel is commonly used) matrix. Due to the fact that DNA is negatively charged, they tend to move towards a positively charged electrode called ANODE.
However, the smaller the size of the DNA fragment, the faster and farther it moves along the matrix. Gel electrophoresis is indeed a technique used to check how progressive a restriction enzyme has been able to digest DNA molecule into fragments.